Thousands of police officers could be axed under Conservative cuts plans, according to analysis carried out by Labour.

The Metropolitan Police could lose between 1,300 and 5,200 to meet a black hole in funding, the party's assessment of House of Commons research suggests.

Gareth Thomas, shadow London minister, claimed there is a "real fear" that policing could return to an emergency only service.

The Government insisted police reforms are "working" and said that crime has fallen by more than a fifth since the coalition took power.

Mr Thomas told the Guardian: "George Osborne's plans for cuts in Metropolitan police funding ... would have a devastating impact on the quality of policing in London and be the final death knell for high visibility, bobby on the beat local policing."

He added: "There is now a real fear that what the coalition Government are planning is a return to 1980s-style policing, with people responding to emergencies only rather than proactive community policing which, until recently, people have come to expect.

"This gives the police better access to intelligence about what is going on in the community, about where potential criminal activity may take place and the police are able to be much more pro-active about getting access to that sort of intelligence.

"If there are fewer police they will have to rely on people phoning as a result of an emergency rather than getting access to that intelligence.

"This might have sounded like a good idea to George Osborne and the small circle he moves but this is not the standard of policing people have come to expect and want."

At Labour's request, the House of Commons library assessed what the impact on police numbers would be if the Met tried to met a shortfall of £400 million in funding by cutting staff and found up to 5,194 posts would be at risk. It did not include other areas where savings could be made in the assessment.

Policing minister Mike Penning said: "Police reform is working and crime has fallen by more than a fifth under this Government according to the independent Crime Survey for England and Wales.

"There is no question police will still have the resources to do their important work. Her Majesty's Inspectorate of Constabulary recently found that forces can successfully manage to balance their books while protecting the frontline and delivering reductions in crime.

"We have made it easier for the police to do their job by cutting red tape, scrapping unnecessary targets, and giving them the discretion to use their professional judgement.

"And in its Peel assessment of the Metropolitan Police Service (MPS), HMIC (Her Majesty's Inspectorate of Constabulary) found the force has a good track record for recognising emerging threats and retaining staff in critical posts, including in crime investigation.

"The proportion of police officers on the frontline is growing and HMIC said the MPS has credible plans for dealing with financial pressures.

"The Government is already conducting a fundamental review of the way funding is allocated between force areas. This work is ongoing but we will consult with police forces and others in due course."